Both Canon M3 and Canon 80D have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the M3 and 80D sensor size comparison.
Sensor Size and Resolution Comparison image of Canon M3 and Canon 80D Cameras
Canon M3 and Canon 80D have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Canon M3 and Canon 80D sensors have been tested by DxO and the results show that 80D has a better overall score of 79, 7 points higher compared to M3's score of 72.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon M3
72
22.8 bits
11.8 Evs
1169 ISO
Canon 80D
79
23.6 bits
13.2 Evs
1135 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Canon M3
or the
Canon 80D ,
including hyperfocal distance.
